Hydraulic spring energy store drives for actuating high-voltage circuit breakers are known, for example, from DE 3408909 A1 and EP 0829892 A1, wherein a spring element interacts with a movable storage piston, which is guided in a hydraulic block.
Hydromechanical spring energy store drives can have a working cylinder. A piston of the working cylinder can be connected to a piston rod, which can be movable by means of pressure loading of a pressure volume. The piston rod can be connected to an electrical circuit breaker, and by virtue of the movement of the piston rod, the electrical circuit breaker can be switched. In order to open the electrical circuit breaker, a hydraulic pressure can be applied to the pressure volume in the working cylinder, such that the piston rod can be moved into a corresponding position.
The pressure in the pressure volume can be provided by a pressure cylinder, which can be coupled to a mechanical energy store unit, such as a spring arrangement, for example. If the circuit breaker is to be switched, the spring force can be released onto the pressure cylinder, such that a working or system pressure can be build up in the cylinder, which can also be present in the pressure volume of the cylinder, via a hydraulic connection. Due to the working pressure in the pressure region, the piston and the piston rod of the differential cylinder can be moved.
In order to protect hydromechanical drives of high-voltage circuit breakers from switching off in an undesired manner in the event of pressure loss at the drive, a latch in the form of a latching bolt can be used, which can fix the working piston of the drive in an “ON” position.
During the work involved the first time the system is brought into operation or during maintenance work and in the case of unpressurized slow switching operations, in which the working piston is moved without any drive pressure, the latching bolt needs to be deactivated in order to avoid damage to the hydromechanical drive.
If, during maintenance work, the working piston is to be moved without pressure, the latching bolt attempts to prevent the movement. In order that the latching bolt in this case does not engage, however, the latching bolt should be deactivated in advance since the latch in the form of a latching bolt otherwise operates counter to the movement being performed. If this is disregarded or the latching piston or latching bolt has been set incorrectly, the hydromechanical drive becomes unusable.
In accordance with an exemplary embodiment, the disclosure provides a locking apparatus for a hydromechanical spring energy store drive of a high-voltage or medium-voltage switch, for example, a circuit breaker of a gas-insulated switchgear assembly, which can help avoid the damage to the drive as a result of faulty operation and can save time since the activation and deactivation of the latching bolt is no longer needed.
Furthermore, the disclosure relates to a hydraulic spring energy store drive for a medium-voltage or high-voltage circuit breaker, which includes the locking apparatus also referred to as a blocking apparatus as disclosed.